FTP Upload... bug?

I see this has been hashed over before, but I can not for the life of me get a simple FTP upload to work. No error is thrown, connection tests successful, I can manually upload the same file to the same path with the same creds.

Looking at a packet cap, it seems the activity is trying to change directory to the NAME of the file and not correctly parsing the path string. Same results with root path upload, escaped slashes, backslashes, etc. Version 1.0.7495.12930 of the official FTP activities. Studio 2020.4

I guess there is not directory “up/foo.txt” but just “up/” ?

Correct, there is a directory in the root “/up” into which I’m trying to upload the file as “foo.txt”.
If I specify only a directory in the remote path property, the activity times out.
I can see it performing a confused, infinite loop in the pcap:

Looks correct but maybe connection problem? Can you use SFTP?

Connection from the same endpoint to the same server works just fine (filezilla), same port, same cred.